1. Field of the Invention
The present invention relates to a memory card connector for storing a memory card to connect the memory card to a record reading device.
2. Prior Art
In the prior art, memory cards such as SD cards (registered trademark) or MS cards (registered trademark) include a memory card 4 having single row of pad portions 4a for signals and a new memory card 5 having front-row signal pad portions 5a and a rear-row signal pad portions 5d arranged in parallel in two rows in the front and rear as illustrated in FIGS. 4A and 4B.
A memory card connector 10 configured to store either the above-described new and old memory cards 4 and 5 in a card storage portion without problem includes, as illustrated in FIGS. 4C and 5A, a case 10a having a memory card storage portion and a shell formed of a synthetic resin or a metal, a plurality of rear-row signal contacts 11 whose end portions abut against and electrically connected to rear-row signal pad portions 5d of the memory card 5 and which are partly secured to the case 10a, and signal contacts 3 abutting against and electrically connected to pad portions 4a or the front-row signal pad portions 5a of the memory card 4 or 5 to be stored in the memory card storage portion (JP-A-2012-18863). In the memory cards 4 and 5, a thickness t1 of the pad portion is thinner than a thickness t2 of the case portion by forming a step from a bottom surface of the case portion, as illustrated in FIGS. 5B and 5C.
For the memory card 4 inserted into the memory card storage portion, the rear-row signal contact 11 formed as illustrated in FIG. 6 slides in pressure contact with the pad portion 4a and the case portion 4b respectively as illustrated in FIGS. 7 and 8 when the memory card 4 is inserted into the storage portion. In contrast, when the memory card 5 is inserted into the memory card storage portion, the rear-row signal contact 11 slides in pressure contact with the front-row signal pad portion 5a and the rear-row signal pad portion 5d of the memory card 5.
The distal end portion 11c of the rear-row signal contact 11 is formed to have a single curved surface by bending a metallic foil plate as illustrated in FIGS. 6 to 8. Therefore, the contact position of the contact end 11a for contact with the rear-row signal pad portion that comes into contact with the rear-row signal pad portion 5d and the contact position of the contact end 11b for contact with the case portion of the memory card 4, which depends on the bending angle of the rear-row signal contacts 11, are different. However, as illustrated in FIG. 7 and FIG. 8, the contact positions of the contact end 11a for contact with the rear-row signal pad portion and the contact end 11b for contact with the case portion of the distal end portions 11c are in quite proximity with each other in the same curved surface.
Therefore, although the memory card connector 10 is a connector compatible with both of the memory cards 4 and 5, when the memory card 4 having single row of the pad portions 4a is inserted in and pulled out repeatedly, shavings of the case portion 4b of the memory card 4 may be adhered to the contact ends 11a for contact with the rear-row signal pad portions of the rear-row signal contacts 11, and plated layers near the contact ends 11b for contact with the case portion is subject to wear.
The shavings of the contact ends 11b for contact with the case portion are conveyed by the distal end portion 11c of the rear-row signal contact 11 to the contact end 11a for contact with the rear-row signal pad portion and are adhered thereto, which causes lowering of contact reliability between the rear-row signal pad portion 5d and the rear-row signal contact 11. The memory card connector of the invention is proposed in order to solve the problems described above.